Method and apparatus for cooling lens edge during dry processing

ABSTRACT

A method and apparatus for processing a periphery of a lens includes holding the lens to be processed, providing at least one edge processing system, disposing the at least one edge processing system and the periphery of the lens proximal one another in a processing position, dry edging the periphery of the lens with the at least one edge processing system to a predetermined configuration, and cooling the periphery of the lens during the edging step with a cooling medium other than a liquid.

FIELD OF THE INVENTION

The present invention relates to a method for processing a peripheral edge of a lens, and more particularly, a method of cooling the peripheral edge of the lens during dry edging processes, and an apparatus therefor.

BACKGROUND OF THE INVENTION

An eyeglass-lens processing apparatus for processing a peripheral edge of an eyeglass lens in conformity with the shape of an eyeglass frame is known. With this type of apparatus, the eyeglass lens after being roughly processed is subjected to finish processing by a finish abrasive wheel, and the peripheral edge of the eyeglass lens is further subjected to edge finishing, such as a bevel, polishing, chamfering and/or grooving.

Traditionally, the edging was manually performed by an operator using a so-called hand grinder having a rotating conical abrasive wheel. More recently though, processing apparatuses are provided with a rotating abrasive wheel having different abrasive portions for roughing, finishing, and polishing the lens edge. Examples of edge processing apparatuses include the LE-9000SX/LX/EX/DX Series and the SE-9090 Express manufactured by Nidek Co., Ltd. of Japan.

These type of edge processing apparatuses provide a vast improvement over manual grinding in terms of high speed production, versatility in type of lens material, and precision. Generally, in an apparatus for processing a periphery of an eyeglass lens, the rotating grinding abrasive wheel is caused to press against the periphery of the lens by applying a fixed load between the abrasive wheel and the lens while rotating the lens held on a lens rotating shaft (lens chuck shaft), thereby carrying out the processing. During the rough, finish and polish processing of a glass or plastic lens, water may be supplied in order to cool the lens edge and to remove processing wastes. The used water is discharged through a drain such as a drainage port provided in a lower part of the processing chamber. When rough processing a polycarbonate lens, however, water cannot be used without causing a melting or swarfing of the lens material. Thus, a dry roughing process is performed on a polycarbonate lens, although water can be used to cool the lens edge during the finishing and polishing stages.

As a result of the dry roughing, the high speed processing tends to increase the heat and stress in the eyeglass lens as it is being processed. In turn, the heat build up on the eyeglass lens can lead to lens slippage as it is being held in the lens chuck, as well as causing increased wear of the abrasive wheel. More specifically, the lens chuck generally includes opposing blocks, each of which has an adhesive pad for holding the lens therebetween. The increased heat encountered during the dry roughing process may cause a decrease in the effectiveness of the adhesive pads, and thus tends to cause the lens to slip.

Accordingly, there is a need for a method and apparatus for rough processing the peripheral edge of an eyeglass lens, in particular a polycarbonate lens, in a high speed production process while avoiding swarfing, the build up of heat during processing and the consequences thereof.

SUMMARY OF THE INVENTION

These and other objects of the present invention are satisfied by a method for processing a periphery of a lens, comprising holding the lens to be processed; providing at least one edge processing system; disposing the at least one edge processing system and the periphery of the lens proximal one another in a processing position; dry edging the periphery of the lens with the at least one edge processing system to a predetermined configuration; and cooling the periphery of the lens during the dry edging step with a cooling medium other than a liquid. In a preferred embodiment, a gaseous substance such as cooled, compressed air is directed to an area proximal the periphery of the lens.

A further aspect of the invention provides an apparatus for processing a periphery of a lens, comprising: a lens holding system; at least one edge processing system; control means for controlling operation of the lens holding system and the at least one edge abrasive processing system so as to process the periphery of the lens to a predetermined configuration; and a cooling system for cooling the periphery of the lens during edge processing with a cooling medium other than a liquid.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

These and other objects, features, and advantages of the present invention will become more readily apparent to those skilled in the art upon reading the following detailed description, in conjunction with the appended drawings in which:

FIG. 1 is a schematic drawing of a conventional lens processing apparatus with a cooling apparatus connected thereto in accordance with a preferred embodiment of the present invention.

FIG. 2 is a schematic drawing thereof with the outer housing removed.

FIG. 3 is a perspective view of the inside of the grinding chamber thereof with the cooling apparatus connected thereto in accordance with a preferred embodiment of the present invention.

FIG. 4 is a further perspective view of the inside of the grinding chamber.

FIG. 5 is a perspective view of the nozzle assembly used with the cooling apparatus in accordance with a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, the external configuration of a typical eyeglass-lens processing apparatus, or edger, is generally shown by reference numeral 10. The apparatus 10 may include an eyeglass-frame-shape measuring device 12, such as that disclosed in U.S. Pat. Nos. 5,228,242, 5,333,412, or U.S. Pat. No. 5,347,762 (Re. Pat. No. 35,898), within the main body 1 of the apparatus. A switch panel section 410 having switches for operating the frame-shape measuring device 12 and a display 415 for displaying processing information and the like may be disposed in front of the frame-shape measuring device 12. The apparatus 10 also preferably has a switch panel section 420 having various switches for inputting processing conditions and the like and for giving instructions for processing, and an openable window 402 for gaining access to a processing chamber 405. In accordance with a preferred embodiment of the present invention, a cooling device 20 is connected to the processing chamber 405, as described in further detail below.

FIG. 2 is a perspective view illustrating the arrangement of a typical lens processing section disposed in the casing of the main body 1. A carriage unit 700 is mounted on a base, and a subject lens LE clamped by a pair of lens chuck shafts of a carriage 701 is ground by a group of abrasive wheels 602 attached to a rotating shaft 601. The group of abrasive wheels 602 preferably include a rough abrasive wheel 602 a, a finish abrasive wheel 602 b, and a polishing abrasive wheel 602 c. Different wheels can also be provided for glass, polycarbonate and plastic lenses, and/or the polishing abrasive wheel may be eliminated, or any combination thereof depending upon the desired processing. Still further, more than one group of said abrasive wheels may be provided as in, for example, the Nidek SE-9090 mentioned above. The rotating shaft is rotatably attached to the base by a spindle 603. A pulley 604 is attached to an end of the rotating shaft 601, and is linked through a belt 605 to a pulley 607 which is attached to a rotating shaft of an abrasive-wheel rotating motor 606. Other types of systems for rotating the shaft, as are well known in the art, could of course be provided instead. An optional lens-shape measuring section 500 may be provided in the rear of the carriage 701 and an optional edge processing section 800 may be provided in the front side for certain type of edging, such as chamfering and grooving the periphery of the lens.

Referring also to FIGS. 3 and 4, the present invention provides a cooling apparatus 20 for supplying a cooling medium other than a liquid, e.g., water, glycol, or other liquid coolant, to the lens edge during processing, and in particular, during the dry edging process of a lens, such as a polycarbonate, CR39, or hi-index lens. In a preferred embodiment, the cooling apparatus 20 is a pneumatic cooling device, and more preferably a vortex tube such as vortex tube Model 106-2-h available from C.C.Steven & Associates, Ventura, Calif. The vortex cooling apparatus 20 is preferably self-contained and enclosed in a 6″×6″ (15 cm×15 cm) or similar sized control box 22. The control box 22 can be placed directly next to edging apparatus 10, or if desired mounted up to approximately 30″ (0.8 m) away from the apparatus 10 in order to reduce the footprint thereof.

When using a vortex tube, air from a standard air compressor (80 psi) enters the vortex tube at approximately 70° F. (21° C.) and is transformed to a temperature of 30°-40° F. (−1°-5° C.) As known in the art in vortex tube operation, compressed air enters a tangentially drilled stationary generator which forces the air to spin down the long tube's inner walls toward the hot air control valve, achieving sonic speeds of up to 1,000,000 RPM. A percentage of this air, now at atmospheric pressure, exits through the needle valve at the hot air exhaust. The remaining air is forced back through the center of the sonic-velocity airstream where, still spinning, it moves at a slower speed, causing a simple heat exchange to take place. The inner, slower-moving air column gives up heat to the outer, faster moving air column. When the slower inner air column exits through the center of the stationary generator and out the cold exhaust, it has reached a lower temperature, preferably 30°-40° F. (−1°-5° C.) when exiting the cooling apparatus 20.

The cooling apparatus 20 is arranged for use with the edging apparatus 10 by attaching a flexible tube 24 to the cold air exhaust and running the flexible tube 24 to the internal processing chamber of edging apparatus 10. The other end of flexible tube 24 is connected to a nozzle assembly 26, which is directed to the point of the lens contacting the roughing wheel 602 a. If the edging apparatus has more than one group of abrasive wheels 602, the cooling apparatus 20 preferably includes a nozzle assembly 26 for each dry roughing wheel thereof. As illustrated in FIG. 5, in a preferred embodiment, the nozzle assembly 26 includes a flat nozzle or a flat angled nozzle 28, such as Model Nos. 920, 921, or 961 available from Silvent AB of Boras, Sweden, connected via a ball swivel joint 30 so as to accurately direct the cooling medium to the point of contact and reduce noise. It has been found that by supplying the cooled air from cooling apparatus 20 to the edge of the lens, the build up of heat in the lens is reduced and consequently, the adhesive pads of the lens chuck are better able to maintain the lens in position. Hence, lens slippage is reduced.

In order to install the cooling apparatus 20 for use with a conventional edger, such as the Nidek 9000 EX Edger, the following preferred method of installation is followed. A hole 32 having a preferred diameter of 7/16 inch (1.11 cm) is first drilled in the front inside panel of the grinding chamber 405. The center of the drilled hole is preferably oriented 5 cm (1.9″) from the left side of the grinding chamber and 1 cm (0.4″) below the top of the lower panel to allow adequate clearance for the groove arm of the edge processing section 800 to raise and lower unrestricted. This hole 32 will be the location of the mounting of the nozzle assembly 26.

A threaded connector, such as a LOC-LINE connector, is placed inside the drilled hole 32, from the inner side of the grind chamber 405. A brass elbow fitting is preferably placed opposite the LOC-LINE fitting, on the front out-side of the grinding chamber 405 and the two fittings are threaded together and tightened until snug and securely mounted. As known in the art, washers can be used as spacers if necessary to provide a tight fit.

A preferably ¼ inch (0.635 cm) diameter hole is drilled wherever convenient through the rear panel of the apparatus 10 to run the tubing 24 through, and out to the cooling apparatus 20. The tubing 24 is preferably water resistant since it will be used within the grinding chamber where water is used to cool glass and plastic lenses. A typical tubing would be PUN-H blue tubing available from Festo Corporation, Hauppauge, N.Y. The opposite end of the tubing is connected inside the apparatus 10 to an appropriate fitting attached to the brass elbow fitting at the grinding chamber 405. The tubing 24 thus defines the cold line for delivery of the cooled air to the nozzle assembly 26. Since tubing 24 will be delivering cooled air, it is preferred that this line be properly insulated throughout the entire inside of the machine to prevent condensation from gathering and potentially damaging the edger apparatus 10. It is also important to ensure that the tubing line 24 does not rest anywhere that would restrict movement of motor axes.

After the nozzle assembly 36 and cold line 24 have been affixed to their proper locations, the cooling apparatus 20 can be placed anywhere desired outside of the apparatus and the cold line 24 connected to an appropriate fitting, preferably marked “Air OUT” on the cooling apparatus 20. Compressed air is supplied to the cooling apparatus 20 by using the female cable in the back of the edger preferably labeled “Pump 2” and plugging it into the matching male cable on the cooling apparatus 20. The remaining female cable from the cooling apparatus 20 is then plugged into the edger apparatus 10 where the female cable was just removed. Afterward, tubing is connected to the appropriate fitting, preferably marked “Air IN” on the cooling apparatus 20, and the other end of the tubing is connected to any available compressed air supply. As the “Air IN” tubing line is not cold, it does not need to be insulated.

The last step is to adjust the air regulator knob 34 to the desired air pressure (preferably 80 psi (5.6 kg/cm²)), and adjust the temperature with the cooling regulator or hot air exhaust knob 36. The cooling apparatus 20 will preferably only be activated when the switch 38 is in the ON position and the water curtain (optional) of the edger apparatus 10 is activated simultaneously. Preferably, the cooling apparatus 20 is automatically energized when apparatus 10 is cycled on. Additionally, the cooling apparatus 20 can preferably be manually turned off when edging plastic or glass lenses by turning switch 38 to the OFF position. Normally plastic and glass lenses use water and do not require cooling; thus, by turning off the cooling apparatus 20 un-needed air would not be consumed.

Although only preferred embodiments and examples are specifically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings including, but not limited to, the application of the claimed invention to other types of lenses other than eyeglass lenses, lenses made of materials other than those specifically mentioned herein, and other types of edge processing systems other than abrasive systems or abrasive wheels. All of such modification and variation are deemed within the purview of the appended claims without departing from the spirit and intended scope of the invention. 

1. A method for processing a periphery of a lens, comprising: holding the lens to be processed; providing at least one edge processing system; disposing the at least one edge processing system and the periphery of the lens proximal one another in a processing position; dry edging the periphery of the lens with the at least one edge processing system to a predetermined configuration; and selectively cooling the periphery of the lens during the dry edging step with a liquid or with a cooling medium other than a liquid.
 2. The method of processing as recited in claim 1, wherein cooling the periphery of the lens includes directing a gaseous substance thereto.
 3. The method of processing as recited in claim 2, wherein cooling the periphery of the lens includes directing cooled, compressed air thereto.
 4. The method of processing as recited in claim 1, wherein cooling the periphery of the lens includes supplying compressed air to a cooling apparatus, cooling the compressed air, and directing the cooled, compressed air to the periphery of the lens.
 5. The method of processing as recited in claim 4, wherein supplying compressed air to a cooling apparatus includes supplying compressed air at a temperature of approximately 70° F. (21° C.) to the cooling apparatus.
 6. The method of processing as recited in claim 4, wherein supplying compressed air to a cooling apparatus includes supplying compressed air to a vortex tube.
 7. The method of processing as recited in claim 4, wherein directing the cooled, compressed air includes directing compressed air at a temperature of approximately 30° F.-40° F. (−1° C.-5° C.) to the periphery of the lens.
 8. The method of processing as recited in claim 4, wherein directing the cooled, compressed air includes delivering the cooled, compressed air from the cooling apparatus to a nozzle assembly disposed proximal the at least one edge processing system and the periphery of the eyeglass lens.
 9. The method of processing as recited in claim 8, wherein delivering the cooled, compressed air to the nozzle assembly includes providing a delivery tubing and insulating the delivery tubing so as to prevent condensation.
 10. An apparatus for processing a periphery of a lens, comprising: a lens holding system for holding a lens; at least one edge processing system; control means for controlling operation of the lens holding system and the at least one edge processing system so as to process a periphery of the lens to a predetermined configuration; and a cooling system for cooling the periphery of the lens during edge processing with a cooling medium other than a liquid.
 11. The apparatus as recited in claim 10, wherein the cooling system comprises a cooling apparatus that directs a gaseous substance to an area proximal the at least one edge processing system and the periphery of the lens.
 12. The apparatus as recited in claim 11, wherein the cooling apparatus directs cooled, compressed air to the area proximal the at least one edge processing system and the periphery of the lens.
 13. The apparatus as recited in claim 11, wherein the cooling apparatus includes an air inlet for receiving a supply of compressed air, means for cooling the compressed air, and an air outlet for directing the cooled, compressed air to the periphery of the eyeglass lens.
 14. The apparatus as recited in claim 13, wherein the air inlet receives the supply of compressed air at a temperature of approximately 70° F. (21° C.).
 15. The apparatus as recited in claim 13, wherein the air outlet directs cooled, compressed air a temperature of approximately 30° F.-40° F. (−1° C. -5° C.) to the periphery of the lens.
 16. The apparatus as recited in claim 13, wherein the means for cooling the compressed air includes a vortex tube.
 17. The apparatus as recited in claim 13, wherein the cooling apparatus further includes a nozzle assembly disposed proximal the at least one edge processing system and the periphery of the lens.
 18. The apparatus as recited in claim 17, wherein the cooling apparatus further includes a delivery tube disposed between the air outlet and the nozzle assembly, the delivery tube being insulated so as to prevent condensation.
 19. The apparatus as recited in claim 10, wherein said at least one edge processing system comprises an abrasive wheel.
 20. The apparatus as recited in claim 10, wherein said lens holding system includes opposing adhesive pads for holding the lens therebetween.
 21. The apparatus as recited in claim 10, wherein the lens comprises an eyeglass lens.
 22. In an apparatus for processing a periphery of a lens comprising a lens holding system; at least one edge processing system; and a control system for controlling operation of the lens holding system and the at least one edge processing system so as to process the periphery of the lens to a predetermined configuration; the improvement comprising: a cooling system including a cooling apparatus for providing a cooling medium other than a liquid to the periphery of the lens during dry edge processing.
 23. The improvement as recited in claim 22, wherein the cooling apparatus includes a compressed air inlet, a cooling device, and a compressed air outlet, said cooling device cooling compressed air to approximately 30° F.-40° F. (−1° C.-5° C.) prior to exiting the compressed air outlet.
 24. The improvement as recited in claim 23, further comprising a nozzle assembly connected to the compressed air outlet, the nozzle assembly directing the cooled, compressed air to the periphery of the lens during edge processing.
 25. The improvement as recited in claim 23, wherein the cooling apparatus includes an air regulator to regulate the pressure of compressed air delivered to the air inlet and a cooling regulator to adjust a temperature of compressed air exiting from the compressed air outlet.
 26. The improvement as recited in claim 22, wherein the cooling system further includes means for providing a liquid to the periphery of the lens during dry edge processing.
 27. An apparatus as recited in claim 10, wherein said cooling system for cooling the periphery of the lens during edge processing selectively cools the periphery of the lens with a liquid or with a cooling medium other than a liquid as determined by a user. 